Warning system and warning method

A warning method comprising the steps of:

• using a computer to perform the steps of:
• a determining step of determining, prior to printing by a printing apparatus of an image based on data obtained after an image processing of image data, whether or not there is a possibility in which an undesirable printing result may be caused based on the image data;
• a region separation step of separating the image data into regions having different attributes;
• a determination step of determining whether each of the regions having different attributes may cause an undesirable printing result;
• and
• a data forming step of simulating, when it is determined that there is the possibility in which the undesirable printing result may be caused, the image processing by the printing apparatus to form the data after the image processing with respect to thus determined image data;
• and
• using a display to perform the step of:
• a display step displaying, prior to printing of the image by the printing apparatus, a preview image based on the data after the image processing.